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Correctness argument Let pi be the correct process with the smallest id in a run R. Assume pi decides v. If i = n, then pn is the only correct process. Otherwise, in round i < n, all correct processes receive v and will not decide anything different from v.

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Zooming in a round To decide, leader executes steps 1-2-3 1. leader selects among a majority the latest adopted value (latest with respect to the round in which the value is adopted –step 2) 2. leader imposes that value at a majority: any process in that majority adopts that value – pi fails if it is suspected 3. leader decides and broadcasts the decision to all